Double lever flush latch



June 2, 1970 'R. PO E DOUBLE LEVER FLUSH LATCH 2 Sheets-Sheet 1 Filed March 26, 1968 INVENTOR. 40m E/C/m/QD P05 W Q i flrro/e/vfys June 2, 1970 R. POE 3,515,422

DOUBLE LEVER FLUSH LATCH Filed March 26, 1968 2 Sheets-Sheet L) Flt T 6' 1 N VE N TOR. 14am E/CfiA/QD P05 A Tram/5V5 United States Patent O 3,515,422 DOUBLE LEVER FLUSH LATCH Lloyd Richard Poe, Los Angeles, Calif., assignor to Hartwell Corporation, Los Angeles, Calif., a corporation of California Filed Mar. 26, 1968, Ser. No. 716,211

Int. Cl. Ec 19/14 US. Cl. 292-113 9 Claims ABSTRACT OF THE DISCLOSURE A latch particularly intended for cowl doors of high speed aircraft which, when latched, is disposed flush with the surrounding surface. The latch includes two tandem disposed and pivotally connected levers, one lever having a hook for engagement with a keeper and the other lever, which forms a handle, being provided at its extremity with an externally accessible secondary or trigger latch for securing the levers in a flush condition.

SUMMARY OF THE INVENTION This invention is intended primarily for use with cowl doors of high speed aircraft, and included in the objects of this invention are:

First, to provide a latch having two tandem disposed levers one of which is pivotally connected directly to the cowl door and forms a handle; whereas, the second lever is pivotally connected to the first lever and is provided with a catch for engagement with a keeper; the levers being so arranged that the first lever may pivot 180 if desired.

Second, to provide a double lever latch, of the type indicated in the preceding object, which, when the latch levers have been moved to effect initial opening of the cowl door, the second lever remains hooked to the keeper to prevent inadvertent dropping of the cowl door if installed on the underside of the aircraft; the catch, however, being readily lifted and moved free of its keeper to permit full opening of the cowl door.

Third, to provide a double lever latch, of the type indi cated in the preceding objects, wherein the latch is secured by a tension connection between the hook of the second lever and the keeper; however, should the tension load relax completely, the latch prevents the cowl door from opening.

Fourth, to provide a double lever latch, of the type indicated in the preceding objects, which incorporates an externally accessible secondary or trigger latch mounted on the first or primary lever for securing both levers, and the trigger latch as well, in a flush condition.

DESCRIPTION OF THE FIGURES FIG. 1 is a side view of the double lever flush latch, with portions shown in section, and showing the keeper pin and its mounting, fragmentarily.

FIG. 2 is a bottom view of the latch, with the keeper pin shown fragmentarily, and with portions of the panel to which the latch is fastened, indicated by broken lines.

FIG. 3 is a fragmentary side view, taken within circle 3 of FIG. 1, showing the latch in its open position, but still in engagement with the keeper pin, the panel to which the latch is attached being indicated by broken lines.

FIG. 4 is an end view of the latch, shown in its folded condition, taken from 4-4 of FIG. 3.

FIG. 5 is an enlarged fragmentary sectional view, taken through 5-5 of FIG. 2.

FIG. 6 is an enlarged fragmentary sectional view, taken through 6-6 of FIG. 1.

3,515,422 Patented June 2, 1970 SPECIFICATION The double lever flush latch is intended primarily for use on aircraft, for securing cowl panels or the like. For purposes of illustration, the latch is shown as employed on a cowl panel disposed at the underside of an aircraft.

The double lever flush latch includes an elongated handle lever 1, having a flush side 2; that is, a side which when the latch is in its secured position, is flush with the adjacent surface of the panel in which the latch is mounted. Near one end, opposite sides of the handle lever are provided with recessed surfaces 3. At this end, the handle lever has a transverse journal bore which receives the journal portion of a pivot screw 4. The pivot screw is adapted to be secured into the adjacent door or panel A, indicated by broken lines and fragmentarily in several of the views.

The second of the two levers forming the latch is a catch lever 5, having parallel arms 6 which overlie the recessed surfaces 3 and have edges 7 adapted to occupy a flush position relative to the flush side 2 of the handle lever. The arms 6 are pivotally connected to the handle lever 1 adjacent the pivot screw 4 by a pivot pin 8. Immediately beyond the handle lever 1, the arms 6 are joined by a flush connecting web 9.

The parallel arms 6 are notched to extend partially around the pivot screw 4, and project inwardly from the connecting web 9. The parallel arms are joined together by a hook end 10 which extends laterally from the pivot screw 4 and engages the keeper pin 11, mounted in a pin support 12, forming a part of the structure which surrounds the door or panel A. The pin support is provided with a flush portion 13.

The end of the handle lever 1, remote from the pivot screw 4, is provided with a longitudinal slot 14, and inwardly from the slot, is provided with parallel flanges 15, between which is journalled a trigger lever 16 by means of a pivot pin 17. One side of the trigger lever forms a side 18 which when the lever is in one extreme position, is flush with the flush side 2 of the handle lever. Inwardly from the pivot pin 7, the trigger lever is provided with a hook 19, adapted to engage a retainer pin 20 suitably secured to the door or panel A. Clearance notches 21 are provided in the flanges 15.

One extremity of the side 18 is offset to overlie an end of the slot 14 and thus forms therewith mating stop surfaces 22 which engage when the side 18 is flush with the side 2 of the handle lever. A spring 23 coiled around a retainer pin 24 is positioned between the flanges 15 and is provided with an extremity which bears against the trigger lever to hold the side 18 in its flush position.

Extending into the trigger lever 16, from the flush side 18, is a tool receiving socket 25.

Operation of the dual lever flush latch is as follows:

When the latch is in its secured position, the side 2 of the handle lever 1, the edges 7 of the arms 6, the connecting web 9 and the side 18 of the trigger lever 16 are all flush with each other and with the flush portion 13 as well as flush with the surface of the door or panel. The trigger lever 16 by means of its hook 19 is retained by the pin 20 so that the handle lever cannot be pivoted from its flush position. Also, a plane common to the keeper pin 11 and pivot screw 4 is located outwardly with respect to the axis of the pivot pin 8. That is, the pivot pin is past center so that tension loads on the keeper pin 11 tend to urge the handle lever toward its secured or flush position.

The dual lever flush latch is moved to its open position by first inserting a tool, such as a screwdriver or rod, into the socket 25, then rotating the trigger lever 16 clockwise, as viewed in FIG. 1, to cause the hook 19 to disengage the pin 20. Without removing the tool, the

tool is rotatedin a clockwise direction about the axis of the pivot screw 4, that is, the handle lever 1 and the tool move in unison in a clockwise direction until at least the handle lever is moved far enough from its secured position to permit direct manual engagement.

This movement of the handle lever not only pivots the handle lever with respect to the catch lever 5,. but also causes the catch lever to pivot clockwise about the pin support 12. When the handle lever has been rotated approximately a half turn, and the catch lever approximately a quarter turn, the levers are in the position shown in FIG. 3, the adjacent portion of the door or panel A has been moved outwardly from the surrounding surface. It will be noted that the hook end It remains engaged with the keeper pin 11. Thus, if the door or panel is disposed under an aircraft, the panel does not fall free. Instead, the panel may be lifted slightly and the catch lever 5 turned by engagement with the parallel arms 6 to disconnect it from the pin support 12.

When it is desired to secure the panel and the latch, the end 10 is hooked over the keeper pin 11 whereupon the handle lever 1 is rotated counterclockwise toward its initial position. This effects a corresponding movement of the catch lever. It will be noted that as the two levers come into alignment, a substantial drawing force can be exerted against the keeper pin 11 so as to ensure that the panel and the surrounding structure are brought into proper registry with each other and to make sure that the panel is securely held. As the handle lever is pressed to its secured position, the triggerlever 16 engages the retainer pin 20, securing the handle lever in place.

While a particular embodiment of this invention has been shown and described, it is not intended to limit the same to the details of the construction set forth, but instead, the invention embraces changes, modifications and equivalents of the various parts and their relationships.

I claim:

1. A double lever latch adapted to be mounted in :1

panel for securing the panel to a surrounding frame in which is provided a keeper pin, there being a biasing force applied to said panel tending to move said panel out of said frame, said latch comprising:

(a) a handle lever;

(b) a first means pivotally connecting said handle lever to said panel for approximately half-circle movement;

(c) a catch lever engageable with said keeper pin;

(d) a second means pivotally connecting said levers to permit approximately a quarter-circle movement of said catch lever with respect to both said keeper pin and said handle lever during half-circle movement of said handle lever while said catch lever is held engagcd to said keeper pin by said biasing force, said catch lever thereupon being manipulable for disengagement from said keeper pin.

2. A latch, as defined in claim 1, wherein:

(a) said handle lever and said catch lever have surfaces adapted to be disposed flush with the surrounding surface of said panel; and

(-b) said second pivot means is disposed beyond a plane passing through said pivot means and said keeper pin when said lever surfaces are in their flush condition.

3. A double lever latch, as defined in claim 2, which cooperates with a trigger latch pin incorporated in said panel, said double lever latch further comprising:

(a) a trigger latch mounted in said handle lever at its end remote from said catch lever, said trigger lever being engageable with said trigger lever pin when said handle and catch levers are flush with the surface of the surrounding panel.

4. A latch, as defined in claim 3, wherein:

(a) said trigger lever is provided with an exposed tool receiving socket whereby said trigger lever may be pivoted by a tool clear of said pin and thereupon move the extended end of said handle lever clear of said panel.

5. A double lever latch adapted to secure a flush panel within the underside of a surrounding structure against gravitational force, the panel being recessed to receive said latch for engagement with a keeper pin fixed in the surrounding structure, said latch comprising:

(a) an elongated handle lever pivotally connected near one end to said panel;

(b) a catch lever pivotally connected to said handle lever further from said end than the pivotal axis of said handle lever and extending beyond said end for engagement with said keeper pin;

(c) said levers having a secured position in tandem relation and flush in said panel; said handle lever being pivotable downwardly from its flush position to effect a corresponding pivotal movement of said catch lever about the axis of said keeper pin in depending relation therewith until said panel is displaced downwardly from the surrounding structure; said catch lever thereupon being manipulable for disengagement from said keeper pin.

6. A double lever latch, as defined in claim 5, which with a retaining pin fixed in said panel, said double lever latch further comprising:

(a) a trigger latch mounted in said handle lever at its end remote from said catch lever, said trigger lever being movable between a position flush with said handle lever in which said trigger lever is engageable with said retaining pin and a tilted position disengaging said retaining pin.

7. A latch, as defined in claim 6, wherein:

(a) said trigger lever is provided with an exposed tool receiving socket whereby said trigger lever may be pivoted by a tool clear of said pin and thereupon move the extended end of said handle lever clear of said panel.

8. A double lever latch which is adapted to be fitted in a surrounding frame and subjected to a biasing force urging the panel from the frame, the frame having a keeper pin for engagement by said latch, said latch comprising:

(a) a handle lever;

(b) a first means pivotally connecting said handle lever to said panel;

(c) a catch lever;

(d) and a second means pivotally connecting said catch lever to said handle lever; said catch lever being pivotable about said keeper pin under urge of said biasing force upon pivotal movement. of said handle lever to dispose said panel in offset relation to said frame;

(c) said catch lever being manipulable in opposition to said biasing force for disengagement from said keeper pin. 7

9. A latch, as defined in claim 8, wherein:

(a) the biasing force is a gravitational force;

(b) and said panel and catch lever are adapted to be suspended from said keeper pin.

References Cited UNITED STATES PATENTS MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE, Assistant Examiner U.S. Cl. X.R. 292F108 

